The fusion of mouse myeloma cells and spleen cells from immunized mice by Kohler and Milstein in 1975 (Nature 256: 495-497, 1975) demonstrated for the first time that it was possible to obtain a continuous cell line making homogeneous (so-called "monoclonal") antibody. Since this seminal work, much effort has been directed to the production of various hybrid cells (called "hybridomas") and to the use of the antibody made by these hybridomas for various scientific investigations.
The analysis of lymphocyte populations in human lymphoid tissues has been greatly facilitated by the availability of monoclonal antibodies directed against lymphoid differentiation antigens. These reagents have been used to localize lymphocyte subsets topographically in the lymph node, spleen, and thymus and to phenotype lymphoid malignancies for the diagnosis and classification of the non-Hodgkin's lymphomas and leukemias.
An increasing number of monoclonal antibodies directed at B-cell surface antigens have been reported. Among the commercially available products are monoclonal antibodies to each of the heavy and light chain immunoglobulin classes. Other available reagents include BA-1 (Ambramson, C. S., Kersey, J. H., and LeBien, T. W. J. Immunology 125: 83-88, 1981), B1 (Nadler, L. M., Ritz, J., Hardy, K., Pesando, J. M. J. Clin. Invest. 67: 134-140, 1981) B2 (Nadler, L. M., Stashenko, P., Hardy, R., Van Agthoven, A., Terhorst, C., and Schlossman, S. F. J. Immunol. 126: 1941-1947, 1981), BL1, BL2, and BL3 (Wang, C. Y., Azzo, W., Al-Katib, A., Chiorazzi, N., and Knowles, D. M. J. Immunol. 133: 684-691, 1984), OKB1, OKB2, OKB4, and OKB7 (Mittler, R. S., Talle, M. A., Carpenter, K., Rao, P. E., and Goldstein, G. J. Immunol. 131: 1754-1761, 1983) and others. Although these monoclonal antibodies have been found to identify B-cell differentiation antigens, many cross-react with non-lymphoid tissues, have relatively low avidity of binding, or are directed against antigens which are shed into the blood. Hence, B-Cell specific monoclonal antibodies with in vivo diagnostic or therapeutic potential have not been described to date.